In libraries and on the Internet you can find books, magazines, encyclopedias, lab reports, historical documents, audio and video recordings, and all sorts of other information sources, all of which are useful for different purposes. Deciding which will suit your purpose is an important early step in the research process.
Three basic types of resources:
To know where to go for information, it is useful to know how information is produced; here is a very general overview. (note that these are not rigid distinctions; the same resource can overlap categories.)
Work backwards. Usually, your research should begin with tertiary sources:
Here's a brief list of some of the sources you can find in each of these categories; remember, there are many more: